The field of the present disclosure relates generally to turbine engines and, more specifically, to a fuel nozzle for use with a turbine engine.
Rotary machines, such as gas turbines, are often used to generate power for electric generators. Gas turbines, for example, have a gas path which typically includes, in serial-flow relationship, an air intake, a compressor, a combustor, a turbine, and a gas outlet. Compressor and turbine sections include at least one row of circumferentially-spaced rotating buckets or blades coupled within a housing. At least some known turbine engines are used in cogeneration facilities and power plants. Such engines may have high specific work and power per unit mass flow requirements. To increase operating efficiency, at least some known gas turbine engines may operate at increased combustion temperatures. Engine efficiency generally increases as combustion gas temperatures increase.
However, operating known turbine engines at higher temperatures may also increase the generation of polluting emissions, such as oxides of nitrogen (NOX). Such emissions are generally undesirable and may be harmful to the environment. To facilitate reducing NOx emissions, at least some known gas turbine plants use selective catalytic reduction (SCR) systems. Known SCR systems convert NOx, with the aid of a catalyst, into elemental nitrogen and water. However, SCR systems increase the overall costs associated with turbine operation.
At least some known fuel injection assemblies attempt to reduce NOx emissions by using pre-mixing technology. In such assemblies, a portion of fuel and air is mixed upstream from the combustor to produce a lean mixture. Pre-mixing the fuel and air facilitates controlling the temperature of the combustion gases such that the temperature does not rise above a threshold where NOx emissions are formed. Some known fuel injection assemblies include supplemental burners that extend through a circumferential wall of a combustor cylinder, wherein the assembly includes passages that deflect air radially inward with respect to the combustor cylinder. However, known supplemental burners may not adequately mix the fuel-air mixture and generally do not have liquid fuel injection capabilities.